Unlock 'The Last One' Mission:
When you have 100% game completion 'The Last One' mission for Franklin will become unlocked at Mt.Chiliad at the indicated location (see image of map below). The hunter in this mission is a reference to the hunter in the 'Birth of the Conservation Movement' mission in 'Red Dead Redemption: Undead Nightmare' where John Marston kills the last Bigfoot.

Race Countdown:
If you hold LB while unarmed during the coundown sequence of a race you will be able to start driving while the countdown appears. This cheat is useful for securing first place position or getting a headstart.

Ammu-Nation discount:
Complete all gun range challenges to get a 10% discount at Ammu-Nation stores. Get a "Gold" rank in all gun range challenges to increase that discount to 25%.

Unlock Story Mode Heist Outfits for Normal Play:
Complete the final Story mission to unlock ALL three characters mission specific outfits, this includes the guard uniforms for the final mission, the character's black outfits for stealth missions,and the police uniforms from mid-games. The heavy ballistic armour and the fireman outfit are not included.

Mission Specific Outfits:
Beat the main Story missions.

100% Shirts:
Attain 100% in game.

Unlock Vehicles:
When you complete the following tasks the corresponding vehicle will become unlocked.

Space Docker:
Collect ALL 50 parts for the spaceship and complete the side mission.

Epsilon Tractor:
Awarded to Michael once you finish the Epsilon Tract mission.

Hot Rod ATV:
Awarded to Trevor for completing ALL Story missions.
Keep Empty Space in Garage:
Always try to keep at least one empty space in your purchased garages for when you find a rare vehicle you want to save. If you don't the rare vehicle will disappear when you try and load your garage to remove a vehicle to make a space.

Getting Characters to Drive Themselves:
During gameplay set a new waypoint on the map and then switch to a different character. When you do this this the other character will drive to the marked waypoint while you play as the new character.

Avoid Wanted Level at Airport:
If you have the money this can be easily done by purchasing a plane hanger when you enter the airport.

Custom Shop:
When you play as Franklin you will eventually have the option to purchase a Los Santos Customs shop. If you decide to purchase it you will be able to repair and upgrade your vehicles for free.

Garage:
If you have purchased a garage you can repair damaged vehicles by driving it there and leaving it in storage and then exiting the garage with another vehicle. When you re-enter the garage your previously damaged vehicle will now be completely repaired.

Instantly Fix Damaged Vehicle Free:
If the vehicle you are in is damaged you can instantly repair it if you switch to a different character and then immediately switch back.
Jaws Easter Egg:
You will need a jet ski or boat to obtain this Easter egg as it involves going out into the ocean. When you are out in the ocean you need to keep an eye on the red dot on the rader and when it bounces off your jet ski or boat dive under the water. You will then encounter the great white shark who will eventually decide to attack and eat you. This will earn you the 'Out of Your Depth' Achievement.